fixed #1620 document frequency for RT index, multi-index query, local indexes of distributed index
added SphinxQL OPTION local_df=1
added regressions to test 205

git-svn-id: http://sphinxsearch.googlecode.com/svn/trunk@4014 8b96e2b9-35c5-2c16-bc47-5122d61876d4
fixed #1620 document frequency for RT index, multi-index query, local indexes of distributed index
added SphinxQL OPTION local_df=1
added regressions to test 205

git-svn-id: http://sphinxsearch.googlecode.com/svn/trunk@4015 8b96e2b9-35c5-2c16-bc47-5122d61876d4